Article history: Received 30 September 2011 Received in revised form 22 February 2012 Accepted 20 March 2012 Available online 28 March 2012

The CORDIC algorithm provides an efficient method of computing trigonometric functions by rotating a vector through some angle, specified by its coordinates. This rotation is obtained by performing a number of micro rotations through elementary rotation angles, into which the total rotation angle has been decomposed. This paper presents the design and implementation of a runtime reconfigurable ...

Demand monitoring equipment is installed in each factory or office, and is linked to the Mitsubishi Electric Head Office via the intranet, where a centralized monitoring server provides comprehensive control (Fig. 1). The multi-demand viewer uses its wide-area control function to collect electric power data from each site in real time, and sends out an alert e-mail when there is a high probabil...

A technique is described to dynamically limit power dissipation in heavily pipelined digital circuits. Stages in the pipeline are clock gated based upon validity of data at that stage. As the pipe approaches a stalled or inactive state, branches of the clock tree are progressively disabled stage by stage. The technique has the additional advantage of removing gaps or “bubbles” in the data strea...

In Wireless Ad hoc networks (WANETs), nodes separated by considerable distance communicate with each other by relaying their messages through other nodes. However, it might not be in the best interests of a node to forward the message of another node due to power constraints. In addition, all nodes being rational, some nodes may be selfish, i.e. they might not relay data from other nodes so as ...

This paper reviews existing power management techniques on wireless LAN and verifies the effects of different power management techniques applied to the case for VoIP over WiFi through experiments. Voice communication imposes timely constraints such as short time interval between packets and the need to be always listening for potential incoming connections. It also poses opportunities related ...

This paper presents a mechanism that improves the energy efficiency of PSM (Power Saving Mechanism) specified for DCF (Distributed Coordination Function) in IEEE 802.11. In PSM, time is divided into beacon intervals. At the start of each beacon interval, every node stays awake for a duration, called the ATIM Window. During the ATIM window, nodes exchange control packets to determine whether the...

Power consumption is rapidly increased in data centers because the number of data center is increased and more the scale of data center become larger. Therefore, it is one of key research items to reduce power consumption in data center. The peak power of a typical server is around 250 watts. When a server is idle, it continues to use around 60% of the power consumed when in use, though vendors...

To extend lifetime of battery-powered mobile device before its recharging in broadband wireless access networks, power saving mechanism in MAC (medium access control) has become a significant design issue. Basically, a power saving mechanism is manipulated by adjusting operating parameters such as the minimum sleep interval (Tmin) and the maximum sleep interval (Tmax). In this paper, we propose...

Wireless sensor networks are employed in several applications, including military, medical, environmental and household. In all these applications, energy usage is the determining factor in the performance of wireless sensor networks. Consequently, methods of data routing and transferring to the base station are very important because the sensor nodes run on battery power and the energy availab...